Comparison of the Norwegian knee arthroplasty register and a United States arthroplasty registry

[Tranexamic acid in orthopedic surgery]

Perioperative bleeding may require blood transfusions, which are sometimes not without complications and risks, with the subsequent increase in health care costs. Among other prevention methods, treatment with tranexamic acid (ATX) has shown to be effective in reducing surgical blood loss, especially in the immediate postoperative period. In this regard, studies evaluating ATX in orthopedic surgery show that it is effective and safe when administered intravenously or intra-articularly. The usual evaluated intravenous doses range between 10mg/Kg and 20mg/kg or a fixed dose of 1g to 2g; while intra-articularly, it varies between 250 mg and 3g. ATX, as an anti-fibrinolytic has a potential thrombotic effect, thus it is contraindicated in those patients at risk or with a history of thrombosis. Its topical administration may be safer, but studies are needed to confirm this.

A Review on the Management of Hip and Knee Osteoarthritis

Arthritis is the most common chronic condition affecting patients over the age of 70. The prevalence of osteoarthritis increases with age, and with an aging population, the effect of this disease will represent an ever-increasing burden on health care. The knee is the most common joint affected in osteoarthritis, with up to 41% of limb arthritis being located in the knee, compared to 30% in hands and 19% in hips. We review the current concepts with regard to the disease process and risk factors for developing hip and knee osteoarthritis. We then explore the nonsurgical management of osteoarthritis as well as the operative management of hip and knee arthritis. We discuss the indications for surgical treatment of hip and knee arthritis, looking in particular at the controversies affecting young and obese patients in both hip and knee replacements. Patient and implant related outcomes along with survivorships are addressed as well as the experiences and controversies described in national joint registries.

Strategies to improve clinical research in surgery through international collaboration

More than 235 million patients undergo surgery every year worldwide, but less than 1% are enrolled in surgical clinical trials--few of which are international collaborations. Several levels of action are needed to improve this situation. International research collaborations in surgery between developed and developing countries could encourage capacity building and quality improvement, and mutually enhance care for patients with surgical disorders. Low-income and middle-income countries increasingly report much the same range of surgical diseases as do high-income countries (eg, cancer, cardiovascular disease, and the surgical sequelae of metabolic syndrome); collaboration is therefore of mutual interest. Large multinational trials that cross cultures and levels of socioeconomic development might have faster results and wider applicability than do single-country trials. Surgeons educated in research methods, and aided by research networks and trial centres, are needed to foster these international collaborations. Barriers to collaboration could be overcome by adoption of global strategies for regulation, health insurance, ethical approval, and indemnity coverage for doctors.

Osteolysis around total knee arthroplasty: a review of pathogenetic mechanisms

Aseptic loosening and other wear-related complications are some of the most frequent late reasons for revision of total knee arthroplasty (TKA). Periprosthetic osteolysis (PPOL) pre-dates aseptic loosening in many cases, indicating the clinical significance of this pathogenic mechanism. A variety of implant-, surgery- and host-related factors have been delineated to explain the development of PPOL. These factors influence the development of PPOL because of changes in mechanical stresses within the vicinity of the prosthetic device, excessive wear of the polyethylene liner, and joint fluid pressure and flow acting on the peri-implant bone. The process of aseptic loosening is initially governed by factors such as implant/limb alignment, device fixation quality and muscle coordination/strength. Later, large numbers of wear particles detached from TKA trigger and perpetuate particle disease, as highlighted by progressive growth of inflammatory/granulomatous tissue around the joint cavity. An increased accumulation of osteoclasts at the bone-implant interface, impairment of osteoblast function, mechanical stresses and increased production of joint fluid contribute to bone resorption and subsequent loosening of the implant. In addition, hypersensitivity and adverse reactions to metal debris may contribute to aseptic TKA failure, but should be determined more precisely. Patient activity level appears to be the most important factor when the long-term development of PPOL is considered. Surgical technique, implant design and material factors are the most important preventative factors, because they influence both the generation of wear debris and excessive mechanical stresses. New generations of bearing surfaces and designs for TKA should carefully address these important issues in extensive preclinical studies. Currently, there is little evidence that PPOL can be prevented by pharmacological intervention.

Efficacy of combination of meloxicam and pregabalin for pain in knee osteoarthritis

PURPOSE

Osteoarthritic pain is largely considered to be inflammatory pain. Sensory nerve fibers innervating the knee have been shown to be significantly damaged in rat models of knee osteoarthritis (OA) in which the subchondral bone junction is destroyed, and this induces neuropathic pain (NP). Pregabalin was developed as a pain killer for NP; however, there are no reports on pregabalin use in OA patients. The purpose of this study was to investigate the efficacy of pregabalin for pain in OA patients.

MATERIALS AND METHODS

Eighty-nine knee OA patients were evaluated in this randomized prospective study. Patients were divided into meloxicam, pregabalin, and meloxicam+pregabalin groups. Pain scores were evaluated before and 4 weeks after drug application using a visual analogue scale (VAS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Pain scales among groups were compared using a Kruskal-Wallis test.

RESULTS

Before drug application, there was no significant difference in VAS and WOMAC scores among the three groups (p>0.05). Significant pain relief was seen in the meloxicam+pregabalin group in VAS at 1, 2, and 4 weeks, and WOMAC score at 4 weeks, compared with the other groups (p<0.05). No significant pain relief was seen in the meloxicam only group in VAS during 4 weeks and WOMAC score at 4 weeks compared with the pregabalin only group (p>0.05).

CONCLUSION

Meloxicam+pregabalin was effective for pain in OA patients. This finding suggests that OA pain is a combination of inflammatory and NP.

Influence of preparation techniques to the strength of the bone-cement interface behind the flange in total knee arthroplasty

INTRODUCTION

Recent clinical studies show an increased risk of femoral loosening in high-flexion TKA. Loosening seems to occur behind the anterior flange, which is covering both cancellous bone and cortical bone. It is important to optimize the interface strength between cement and both bone types to increase femoral component fixation. This study was performed to determine the cement-cortical bone interface strength for different preparation techniques.

MATERIAL AND METHODS

A pure tensile and shear force was applied to interface specimens. The cortical surface area was prepared in three different ways: (1) Unprepared cortical bone with periosteum; (2) Periosteum removed and cortical bone roughened with a rasp; (3) Periosteum removed and three Ø 3.2mm holes drilled through the cortex. A reference group was added with a cancellous bone surface.

RESULTS

The interface tensile strength of Group 1 was 0.06 MPa and the shear strength was 0.05 MPa. For Group 2, respectively 0.22 MPa and 1.12 MPa. For Group 3, respectively 1.15 MPa and 1.77 MPa. For cancellous bone a tensile strength of 1.79 MPa and a shear strength of 3.85 MPa were measured.

CONCLUSION

The strength of the cement-cancellous bone interface is superior to the cement-cortical bone interface. The preferred preparation technique of the cortical bone is to remove all the periosteum and drill holes through the cortex within the footprint of the anterior flange, to prevent cortical weakening.

CLINICAL RELEVANCE

Ultimately, the proposed preparation technique will lead to longer implant survival, particularly for prostheses which are used in the high-flexion range.

Patient and implant survival following joint replacement because of metastatic bone disease

BACKGROUND

Patients suffering from a pathological fracture or painful bony lesion because of metastatic bone disease often benefit from a total joint replacement. However, these are large operations in patients who are often weak. We examined the patient survival and complication rates after total joint replacement as the treatment for bone metastasis or hematological diseases of the extremities.

PATIENTS AND METHODS

130 patients (mean age 64 (30-85) years, 76 females) received 140 joint replacements due to skeletal metastases (n = 114) or hematological disease (n = 16) during the period 2003-2008. 21 replaced joints were located in the upper extremities and 119 in the lower extremities. Clinical and survival data were extracted from patient files and various registers.

RESULTS

The probability of patient survival was 51% (95% CI: 42-59) after 6 months, 39% (CI: 31-48) after 12 months, and 29% (CI: 21-37) after 24 months. The following surgical complications were seen (8 of which led to additional surgery): 2-5 hip dislocations (n = 8), deep infection (n = 3), peroneal palsy (n = 2), a shoulder prosthesis penetrating the skin (n = 1), and disassembly of an elbow prosthesis (n = 1). The probability of avoiding all kinds of surgery related to the implanted prosthesis was 94% (CI: 89-99) after 1 year and 92% (CI: 85-98) after 2 years.

CONCLUSION

Joint replacement operations because of metastatic bone disease do not appear to have given a poorer rate of patient survival than other types of surgical treatment, and the reoperation rate was low.

Application and surgical technique of total knee arthroplasties: a systematic comparative analysis using worldwide registers

PURPOSE

The aim of this study was to compare total knee arthroplasty (TKA) procedures between different countries with regard to epidemiological data and surgical technique by reference to the worldwide arthroplasty registers.

METHODS

A systematic search was carried out using the EFORT website to identify the relevant arthroplasty registers. We extracted data with respect to the number of implanted TKAs, patients' age distribution, procedure types, and revision rates. After identification of 28 national arthroplasty registers, 11 offered sufficient data regarding the above mentioned parameters and were therefore included in the final analysis.

RESULTS

A large variation was found in the annual number of primary TKA implantations per inhabitant with a reported range from 30 to 199 per 100,000 (mean 106). The fixation method varied strongly between the different registers as well, e.g. 90 % of totally cemented TKAs in Sweden, England and Wales, Slovakia, and New Zealand versus 54 % cemented fixation in Australia. Another significant difference between included countries was observed with respect to the use of patellar resurfacing in TKA. Whilst the Danish knee arthroplasty register reports a percentage of 72 % using a patellar button in TKA the register from Norway reports only a minority of 2 %.

CONCLUSIONS

The comparison of arthroplasty registers revealed large differences regarding the annual number of primary TKAs per inhabitant and primary TKA procedure types. These variations may be explained by several factors such as patient demographics (prevalence of osteoarthritis) and national conditions such as healthcare systems (insurance status), number or availability of performing surgeons, medical facilities and surgeon-dependent factors such as definition of indications, education, tradition and experience.

Lessons learned from managing a prospective, private practice joint replacement registry: a 25-year experience

BACKGROUND

In 1984, we developed a private practice joint replacement registry (JRR) to prospectively follow patients undergoing THA and TKA to assess clinical and radiographic outcomes, complications, and implant survival. Little has been reported in the literature regarding management of this type of database, and it is unclear whether and how the information can be useful for addressing longer-term questions.

QUESTIONS/PURPOSES

We answered the following questions: (1) What is the rate of followup for THA and TKA in our JRR? (2) What factors affect followup? (3) How successful is this JRR model in capturing data and what areas of improvement are identified? And (4) what costs are associated with maintaining this JRR?

METHODS

We collected clinical data on all 12,047 patients having primary THA and TKA since 1984. Clinical and radiographic data were collected at routine followup intervals and entered into a prospective database. We searched this database to assess the rate of successful followup and data collection and to compare the effect of patient variables on followup. Costs related to database management were evaluated.

RESULTS

Followup was poor at every time interval after surgery, with a tendency for worsening over time. Patients with a complication and those younger than 70 years tended to followup with greater frequency. There were difficulties with data capture and substantial expenses related to managing the database.

CONCLUSIONS

Our findings highlight the difficulties in managing a JRR. Followup is poor and data collection is often incomplete. Newer technologies that allow easier tracking of patients and facilitate data capture may streamline this process and control costs.

Clinical and economic burden of revision knee arthroplasty

Surgery is indicated for symptomatic knee osteoarthritis (OA) when conservative measures are unsuccessful. High tibial osteotomy (HTO), unicompartmental knee arthroplasty (UKA), and total knee arthroplasty (TKA) are surgical options intended to relieve knee OA pain and dysfunction. The choice of surgical intervention is dependent on several factors such as disease location, patient age, comorbidities, and activity levels. Regardless of surgical treatment, complications such as infection, loosening or lysis, periprosthetic fracture, and postoperative pain are known risks and are indications for revision surgery. The clinical and economic implications for revision surgery are underappreciated. Over 55,000 revision surgeries were performed in 2010 in the US, with 48% of these revisions in patients under 65 years. Total costs associated with each revision TKA surgery have been estimated to be in excess of $49,000. The current annual economic burden of revision knee OA surgery is $2.7 billion for hospital charges alone. By 2030, assuming a 5-fold increase in the number of revision procedures, this economic burden will exceed $13 billion annually. It is appealing to envision a therapy that could delay or obviate the need for arthroplasty. From an actuarial standpoint, this would have the theoretical downstream effect of substantially reducing the number of revision procedures. Although no known therapies currently meet these criteria, such a breakthrough would have a tremendous impact in lessening the clinical and economic burden of knee OA revision surgery.

[Arthroplasty registers as post-marketing surveillance systems: the Catalan Arthroplasty Register]

OBJECTIVE

The aim is to present the functioning and results of the Catalan Arthroplasty Registry (RACat).

MATERIAL AND METHOD

The RACat arose by the initiative of the Catalan Society of Orthopaedic Surgery and Traumatology, the Catalan Health Service (CHS) and the Catalan Agency for Health Information Assessment and Quality. Publicly funded hospitals sent information through the Internet (CHS Applications website) on knee and hip arthroplasties: patient identification, hospital, joint (hip/knee), type (primary/revision), side of operation, date of surgery and prosthesis (manufacturer's name and reference number). The quality of the data is analysed regularly. We estimate the risk of replacement by the Kaplan-Meier method.

RESULTS

A total of 52 hospitals out of 62 send data to RACat, and information on 36,951 knee and 26,477 hip arthroplasties is available. Data quality improved between 2005 and 2010. In 2010 coverage exceeded 70%, with side of operation 97%, and prostheses identification of 80%. The risk of replacement at three years was 3.3% (95% CI:3.1-3.6) for knee, 2.9% (95% CI:2.5-3.3) for total hip, and 2.5% (95% CI:2.0-3.1) for partial hip.

DISCUSSION

Risk of replacement is higher than that observed in other registers, although data quality and its improvement over time should be taken into account.

CONCLUSIONS

The information available in the RACat will help to establish a standard that will enable hospitals to compare results.

Existing data sources for clinical epidemiology: The Danish Knee Arthroplasty Register

Purpose

We described the settings, organization, content, and data quality of the Danish Knee Arthroplasty Register (DKR), as well as the incidence and the first results of the knee replacement procedures captured by the DKR. Our aim was to draw researchers’ attention to the DKR and its potential use in clinical epidemiological research.

Patients and methods

The DKR has collected data on all knee replacement procedures performed in Denmark since 1997. The validity of the register was compared with the Danish National Registry of Patients (DNRP). Incidence rate was calculated per 100,000 inhabitants. Implant survival was estimated by Kaplan–Meier method. Cox regression analyses were used to estimate the relative risk (RR) for revision with a 95% confidence interval (CI).

Results

A total of 62,586 primary knee arthroplasties and 6,683 revisions were registered in the DKR between January 1, 1997 and December 31, 2010. More than 90% of the private and public hospitals performing knee replacement surgery in Denmark have entered data to the DKR. Registration completeness of primary procedures and revisions has increased since the DKR initiation and was 88% in 2010 for both procedures, compared with registration in the DNRP. For primary knee arthroplasties, the annual incidence rate increased from 35.8 in 1997 to 155.2 in 2010 per 100,000 inhabitants. Incidence was higher in females than in males during the entire study period, and increased with age for both sexes. The overall implant survival after 14 years was 89% irrespective of diagnosis for surgery. Male patients had higher revision risk than females, and revision risk decreased with increasing age. Risk for any revision was higher for uncemented implants (RR = 1.48; 95% CI: 1.32–1.66), and lower for hybrid implants (RR = 0.84; 95% CI: 0.75–0.95) compared to cemented implants. Implant survival did not improve but remained the same throughout the study period when comparing patients operated in the periods 1997–2000 versus 2001–2003, 2004–2006, and 2007–2010.

Conclusion

The DKR is a valuable tool for quality monitoring and research in knee arthroplasty surgery due to the high quality and completeness of prospective, routinely collected data. Large population-based epidemiological studies can be performed in order to study trends as well as risk factors for poor clinical outcome following knee arthroplasty surgery.

A new method to measure ligament balancing in total knee arthroplasty: laxity measurements in 100 knees

BACKGROUND

Ligament balancing is considered a prerequisite for good function and survival in total knee arthroplasty (TKA). However, there is no consensus on how to measure ligament balance intra-operatively and the degree of stability obtained after different balancing techniques is not clarified.

PURPOSE

This study presents a new method to measure ligament balancing in TKA and reports on the results of a try-out of this method and its inter-observer reliability.

METHODS

After the implantation of the prosthesis, spatulas of different thickness were used to measure medial and lateral condylar lift-off in flexion and extension in 70 ligament-balanced knees and in 30 knees were ligament balancing was considered unnecessary. Inter-observer reliability for the new method was estimated and the degree of medial-lateral symmetry in extension and in flexion, and the equality of the extension gaps and flexion gaps were calculated.

RESULTS

The method was feasible in all operated knees, and found to be very reliable (intraclass correlation coefficient = 0.88). We found no statistically significant difference in condylar lift-off between the ligament-balanced and the non ligament-balanced group, however, there was a tendency to more outliers in flexion in the ligament-balanced group.

CONCLUSIONS

Our method for measuring ligament balance is reliable and provides valuable information in assessing laxity intra-operatively. This method may be a useful tool in further research on the relationship between ligament balance, function and survival of TKA.

Assessment of the suspected fracture of the scaphoid

A suspected fracture of the scaphoid remains difficult to manage despite advances in knowledge and imaging methods. Immobilisation and restriction of activities in a young and active patient must be balanced against the risks of nonunion associated with an undiagnosed and undertreated fracture of the scaphoid.

The assessment of diagnostic tests for a suspected fracture of the scaphoid must take into account two important factors. First, the prevalence of true fractures among suspected fractures is low, which greatly reduces the probability that a positive test will correspond with a true fracture, as false positives are nearly as common as true positives. This situation is accounted for by Bayesian statistics. Secondly, there is no agreed reference standard for a true fracture, which necessitates the need for an alternative method of calculating diagnostic performance characteristics, based upon a statistical method which identifies clinical factors tending to associate (latent classes) in patients with a high probability of fracture.

The most successful diagnostic test to date is MRI, but in low-prevalence situations the positive predictive value of MRI is only 88%, and new data have documented the potential for false positive scans. The best strategy for improving the diagnosis of true fractures among suspected fractures of the scaphoid may well be to develop a clinical prediction rule incorporating a set of demographic and clinical factors which together increase the pre-test probability of a fracture of the scaphoid, in addition to developing increasingly sophisticated radiological tests.